M35A3 Transmision question.

[camp9]

Yep, for $600 it can be like a 6 pack transmission, just have a few on hand.

Camp

 

[steve hendricks]

Thinking Of Buying a M35 A3 Whats The Top Speed With The Allison Transmission , Owner Says Its About 47MPH Is This About Right Or Is There Something Wrong With The Transmission. Thanks For Any Info, Steve

 

[glcaines]

Thinking Of Buying a M35 A3 Whats The Top Speed With The Allison Transmission , Owner Says Its About 47MPH Is This About Right Or Is There Something Wrong With The Transmission. Thanks For Any Info, Steve

The owner is correct. The CAT 3116 engine is not supposed to be run for extended periods over 2500 RPM. I never run my A3 over 45.

 

[flyxpl]

That's about right speed

 

[renovate7]

I also run at 45/47, 2400rpm's.

 

[mktopside]

meh...... It'll do 55 all day long. Put the tires up to 53psi, and just hold the pedal to the floor, you'll be fine.

 

[camp9]

According to my escort with the GPS I can get 52mph out of mine. Switching to the 395 tires so might get a hair more out of it.

Camp

 

[swampzr2]

Mine will top out at 54-55, and those speedo's are right on the money. I usually keep it at 50-51 so I am not screaming. I have heard the CAT motors will run at top speed though.

meh...... It'll do 55 all day long. Put the tires up to 53psi, and just hold the pedal to the floor, you'll be fine.

 

[motomacguyver]

Here is the ending of the story.

I took the truck to the local technical college diesel mechanics program and "donated" my truck to the student’s education. They agreed to remove and replace the transmission. They also stated that they don't do transmission work; they send them to a specialist. The transmission then went to an authorized Allison shop.

The shop found burnt fourth gear clutches, and a torn "o" ring on the piston that actuates the fourth gear clutches. We do not know what happened first, if the "o" ring failed and didn't allow full pressure on the clutches, or if the clutches burnt and the piston was overextended and tore the "o" ring upon retraction. The drive and driven plates were all badly warped and the friction plates didn't have ANY friction material left on them. The transmission has been freshened up with a new clutch pack in fourth and some seals and bushings. The rest of the transmission was in great shape and didn't need any work. It was reassembled and dyno tested, and given a 6 mo. warrantee, and hopefully they sprinkled some holy water on it too. (No offense intended)

The truck is at the tech college and should be ready to go by this weekend. (I hope). Many, Many thanks go out to the guy's at Chippewa Valley Technical College. (whom will be given gift cards)

 

[skd_87]

Well H-E-double hocky sticks fellas, My brand new pride n joy M35A3 has just started doing exactly what MOTOMACGUYVER's did. Got it from Sparta as well. 2000 mi. 3 hundred somthing hours and all of a sudden, the reverse is slipping until you reach 1200rpm. It was fine when I picked it up and drove her home. Then was fine for awhile after that- about 300 miles or so. Then I picked up a load of road stone, just enough to cover the bottom of the bed without spilling out, and all seemed fine shifting, temp, downshifting all good. Then- the next drive after unloading the stone, "slipage" in reverse diddnt notice 4th yet but i would bet it is the same. Krap! Will try all the cheap fixes first as the trans is still holding the original fluid Uncle Sam put in it.

Dannngg.
skd_87

 

[glcaines]

My A3 came from Sparta as well, same auction and low miles/hours So far so good with the Allison transmission. I guess I got lucky. I used the drain and flush method to switch to Dexron III. Dexron III made the transmission operate much smoother. My only complaint with the drive train is difficulty getting the transfer case to shift between high and low. I always have to rock the truck back and forth to be able to shift the transfer case. It is hard to put in low range. It is even harder to get back into high range.

 

[AceHigh]

Gary, I have the same issue. I just figured it was due to little use of the TC with the auto transmission. I use the TC in my A2 often and it shifts easily.

 

[flyxpl]

 

[mktopside]

Here is the ending of the story.

I took the truck to the local technical college diesel mechanics program and "donated" my truck to the student’s education. They agreed to remove and replace the transmission. They also stated that they don't do transmission work; they send them to a specialist. The transmission then went to an authorized Allison shop.

The shop found burnt fourth gear clutches, and a torn "o" ring on the piston that actuates the fourth gear clutches. We do not know what happened first, if the "o" ring failed and didn't allow full pressure on the clutches, or if the clutches burnt and the piston was overextended and tore the "o" ring upon retraction. The drive and driven plates were all badly warped and the friction plates didn't have ANY friction material left on them. The transmission has been freshened up with a new clutch pack in fourth and some seals and bushings. The rest of the transmission was in great shape and didn't need any work. It was reassembled and dyno tested, and given a 6 mo. warrantee, and hopefully they sprinkled some holy water on it too. (No offense intended)

The truck is at the tech college and should be ready to go by this weekend. (I hope). Many, Many thanks go out to the guy's at Chippewa Valley Technical College. (whom will be given gift cards)

Had to have been like that when you bought it. If I remember correctly, it started screwing up the second you changed the oil. No way you could have done all of that damage.

 

[mktopside]

My A3 came from Sparta as well, same auction and low miles/hours So far so good with the Allison transmission. I guess I got lucky. I used the drain and flush method to switch to Dexron III. Dexron III made the transmission operate much smoother. My only complaint with the drive train is difficulty getting the transfer case to shift between high and low. I always have to rock the truck back and forth to be able to shift the transfer case. It is hard to put in low range. It is even harder to get back into high range.

Mine is the same way. It is VERY difficult to get into "low". Getting into high isn't that bad, but I normally just yank the **** out of it and it goes in.

 

[motomacguyver]

Hopefully this is the final installment on my end.

Picked up the truck today from the tech college. They said the transmission was a "female dog" to install. There is a cross member that is in the way. If an upgraded transmission were to be installed, this cross member probably would have to be removed/moved. The Trans install looks like a good job, they used new lock washers, cleaned up after themselves and test drove the truck. – Time will tell the true answer.

Went for a ride, with the 5 year old boy, and got stuck twice! This is as good as it gets, if your 5!! Or 45, (if you don’t have to call the wrecker.)

Anyhow, the winch did the job and we made it home well before dark.

The shifting action is about the same as before, on the up shifting - 1-2 smooth 2-3 a slight overrev and then drops into gear, and the same for 3-4. Downshifting 4-3 a little bump, and then 3-2, and 2-1 come close together and down shift pretty hard. (Moving pretty slowly at this point ~ 20 mph.) We did notice that when climbing a hill that we didn't have enough traction to make; That when backing down in drive, the engine would provide braking action while we were rolling backwards.

We went up and down some stuff that I wouldn’t think of taking my rusty old 4runner through! Had a great time.

 

[AceHigh]

I love a happy ending!

 

[glcaines]

Moto,
It's good to hear that you have your truck back - - and are enjoying it. I noticed that the more I drive my A3, the smoother the transmission shifts. I suspect that even though I did a large number of drain / refill cycles with the Dexron III, that there was still some motor oil trapped in some of the servos that is now being flushed out. My A3 got driven about 175 miles yesterday by a friend (I drove my A2) moving plants. I then drove the A3 about another 10 miles around town and back home. The transmission was shifting the smoothest it has ever shifted. Although your transmission was undoubtedly thoroughly cleaned out when worked on, perhaps it will smooth out also. Both of our trucks had very low mileage. If most of the miles were highway miles (who knows) they may smooth out more with use. My problem is that this is my first experience with an Allison transmission, so I don't really know what is normal behavior.

 

[cattlerepairman]

My problem is that this is my first experience with an Allison transmission, so I don't really know what is normal behavior.

We have a very heavy tandem axle fire truck with an Allison box. It shifts smooth as silk (or so you'd think). Normally, the truck is at max weight, all the time. I just drove it empty (completely stripped of gear, due to upgrades to the box) and without the 2500 imperial gallons of water....and the shifting was actually very noticeable. It felt like a different tranny.

I think that weight etc. has a lot to do with the subjective feeling of how the tranny shifts, even if it works the same, all the time.

 

[AceHigh]

Yes, I have hauled one big load and it made the truck run great! Then I came back empty...